Fix ea jdk selection not just based on major version

explicitly requires to add a ea postfix to the runtime sys property

Author: breskeby

BUILDING.md

@@ -189,11 +189,11 @@ To test an unreleased development version of a third party dependency you have s
 ### How do I test against java early access (ea) versions?
 
 Currently only openjdk EA builds by oracle are supported.
-To test against an early access version java version you can pass the major java version
-to test against via system property (e.g. -Druntime.java=26):
+To test against an early access version java version you can pass the major
+java version appended with `-ea` as a system property (e.g. -Druntime.java=26-ea) to the Gradle build:
 
 ```
-./gradlew clean test -Druntime.java=26
+./gradlew clean test -Druntime.java=26-ea
 ```
 
 This will run the tests using the JDK 26 EA version and pick the latest available build of the matching JDK EA version we expose
@@ -202,7 +202,7 @@ in our custom jdk catalogue at `https://storage.googleapis.com/elasticsearch-jdk
 To run against a specific build number of the EA build you can pass a second system property (e.g. `-Druntime.java.build=6`):
 
 ```
-./gradlew clean test -Druntime.java=26 -Druntime.java.build=6
+./gradlew clean test -Druntime.java=26-ea -Druntime.java.build=6
 ```
 
 #### How to use a Maven based third party dependency via `mavenlocal`?

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/info/GlobalBuildInfoPlugin.java

@@ -347,14 +347,16 @@ private static void assertMinimumCompilerVersion(JavaVersion minimumCompilerVers
     }
 
     private Provider<File> findRuntimeJavaHome() {
-        Integer runtimeJavaProperty = Integer.getInteger("runtime.java");
+        String runtimeJavaProperty = System.getProperty("runtime.java");
+
         if (runtimeJavaProperty != null) {
-            if (runtimeJavaProperty > Integer.parseInt(VersionProperties.getBundledJdkMajorVersion())) {
+            if(runtimeJavaProperty.toLowerCase().endsWith("-ea")) {
                 // handle EA builds differently due to lack of support in Gradle toolchain service
                 // we resolve them using JdkDownloadPlugin for now.
-                return resolveEarlyAccessJavaHome(runtimeJavaProperty);
+                Integer major = Integer.parseInt(runtimeJavaProperty.substring(0, runtimeJavaProperty.length() - 3));
+                return resolveEarlyAccessJavaHome(major);
             } else {
-                return resolveJavaHomeFromToolChainService(runtimeJavaProperty.toString());
+                return resolveJavaHomeFromToolChainService(runtimeJavaProperty);
             }
         }
         if (System.getenv("RUNTIME_JAVA_HOME") != null) {